i'm glad Beyonce never tied herself down to 1 producer....imagine still having albums produced primarily by Scott Storch & Rich Harrison in 2016.
if you hold on to 1 for too long even if its a winning combination...the story is always the same. eventually the chemistry becomes stale & fans, critics, GP alike want you to break away and work with new producers. or they break away on their own after a few albums and the music suffers...everyone wants you to rush back to them...leaving you in a musical box thinking that's the only person you can make good music with.
Beyonce never set up that habit...the core of producers have been different from one album to the next. i think The Dream may be the longest consecutive collaborator...he's made it onto every album since IASF even tho his role has dwindled down to co-writing credit on just 1 song.
she does a good job of mixing 1 or 2 previous old collaborators with new current ones and she always mixes in some underground collaborators that haven't worked with too many people.